Metal expanding machine



May 18, 1965 R. c. SKEEL 3,183,575

METAL EXPANDING MACHINE Filed Feb. 20, 1961 3 Sheets-Sheet 1 INVENTOR. PAY C. 5KEE L.

BYEQZMW ATTORNEY 8, 1965 R. c. SKEEL 3,183,575

METAL EXPANDING MACHINE Filed Feb. 20, 1961 5 Sheets-Sheet 2 52 INVENTOR.

PA v c 5K5 5 L wM/W 48 v w 4a May 18, 1965 R. c. SKEEL METAL EXPANDING MACHINE 3 Sheets-Sheet 3 Filed Feb. 20, 1961 9 4 2 0 (0 (m l l 6 7 W 7 6 m/m H 3 m w% X mm E5 K 5 w 9 a M 3 w United States Patent 3,183,575 METAL EXPANDING MACHHQE Ray C. Skeel, Santa Barbara, Calif., assignor of fifty percent to Robert A. Baker Filed Feb. 20, 1961, Ser. No. 90,425 Qlaims. (Cl. 29-62) My invention relates to machines for expanding sheet metal, and has particular reference to a high speed expanding machine using a reciprocating cutter, that also oscillates.

The term expanded metal generally refers to sheet metal having diamond shaped openings formed therein. The diamond shapes in every other row are aligned and those in adjacent rows are offset by one half the length of the diamond. While diamond shaped openings are most commonly used in industry, various other shapes that interfit each other may be used, such as crescents, ovals, etc. These are used especially for decorative effects. The diamond shapes, however, give maximum utilization of metal and hence are generally preferred.

This expansion of sheet metal is accomplished by slitting the sheet metal with rows of slits with the slits of adjacent rows offset. Various types of slitting mechanisms may be employed. After the metal is slit it is stretched crosswise of the slits to cause the expansion of the metal; that is the formation of the diamond shaped holes. Various types of stretching mechanisms may be employed.

The present invention is an improvement in the old and well known type of expanded metal machine employing a reciprocating cutter. The cutter first slits the metal and as part of the same reciprocating stroke or motion also expands it. The cutter then lifts free of the metal, the sheet metal is advanced, the cutter is moved sideways by one half of a diamond length and then descends again on the metal, cutting a new row of slits and expanding that row to give a row of offset diamonds.

Machines embodying the present invention have cutters that are full floating as contrasted to cutters that move in fixed guides. This full floating action permits very close and accurate adjustment of the cutter to the stationary cutter bar. The general design and construction permits the machine to be operated at a very high rate of speed without impairment of quality of product.

It is therefore a general object of the invention to provide an improved metal expanding machine of the reciprocating cutter type (which cutter also has an oscillating motion).

A further object of the invention is to provide a metal expanding machine having a full floating cutter.

An additional object is to provide a reciprocating expanding machine that can be operated at high speed.

Various other objects, advantages and features of the invention will be apparent in the following description and claims considered together with the accompanying drawings:

FIG. 1 is an elevation View in full section of a metal expanding machine embodying the invention.

FIG. 2 is a sectional view along the line II-IL showing a spring supported yoke for actuating the hold-down.

FIG. 3 is a fragmentary front view of the serrated cutter blade of FIG. 1 for forming the diamond shapes.

FIG. 4 is an elevation view in full section parallel with the crank shaft of the machine.

FIG. 5 is an elevation view of the oscillator arm assembly, one end of which engages the rotary cam on the crank shaft.

FIG. 6 is an elevation view in full section of a portion of the mechanism of FIG. 1, showing the tie rods and springs for holding the reciprocating ram in contact with its bearing plate.

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FIG. 7 is a top view and sectional view along the line VIP-VII of FIG. 6.

FIG. 8 is an elevation view on an enlarged scale of the bronze ball retainer forming the antifriction device disposed by the ram and the bearing plate.

FIG. 9 is a sectional view along the line IXIX of FIG. 8.

Referring to FIGS. 1 and 4, a base may be constructed in the form of a hollow square from two large angle shapes l3 and two smaller angle shapes 14 welded together. Strips of heavy steel 12 may be Welded to the top of each heavy angle 13 and then finished to form two smooth or finished surfaces or ways to which the components may be attached. Spanning between the two finished surfaces 12 is a massive cutter beam 16 having outboard ends that rest on the finished way 12. A hardened steel cutter bar 17 is set on a notch on this support 16 and held in position by a number of screws 18. This stationary cutter bar may be minutely adjusted vertically by a number of set screws 19 (locked by nuts) which in turn lift pins 2]; bearing against the bottom of the cutter bar 17 This lower cutter bar forms one of a pair of shear members. The other is a movable shear blade 22 securely fastened to a massive ram 23 reciprocated toward and away from the stationary cutter bar 17 by a pair of connecting rods 24 energized by a crank shaft 26. To expand sheet materials, the cutting edge of the movable blade is serrated with teeth 25. The movable blade 22 is likewise precisely adjustable in its supporting ram by a pinrality of screws 27 and for this purpose corresponding number of windows 28 are formed in the ram 23.

The crankshaft 25 is supported for rotation in a pair of side plates 29 and 31, having flanges welded to all sides. A pair of H beams 32 are bolted to the top of each side plate 29 and 31 and bearing boxes 34 are bolted to these H beams. A cross member 36 may tie the two H beams together. The crankshaft is driven by a suitable drive wheel 37 keyed or otherwise secured to the shaft and it may act as a flywheel also. The crankshaft 26 has a pair of eccentrics 38 engaged by the connecting rods 24. A central eccentric 39 may be provided to operate the hold-down mechanism of the machine.

Referring especially to FIG. 4, the connecting rods 24 securely engage a wrist pin 41. Bearing blocks 42 slide on this wrist pin 41 and are securely bolted to the ram. The ram 23, accordingly, is free to slide back and forth on this wrist pin 41. As stated previously, on each reciprocation of the ram 23, it isnecessary to slide the ram horizontally one half of the length of a diamond shape on the expanding metal. With reference to PEG. 3 this means one half of the distance between adjoining teeth 25. This is accomplished by means of a rotary cam 43 secured to the crankshaft 26 and having a shaped groove 44 therein engaged by a ball bearing or other rotatable spool 46. This spool 46 is pivoted to the upper end of an oscillating arm 47 having a pivot axis on the bearings 48. This oscillating arm 47 is pin jointed to the ram 23 by link 49, which engages one of the bearing blocks 42.

The oscillating arm 47 is shown in more detail in FIG. 5, wherein this generally Vertical arm is secured to a horizontal bar 51 having the bearings 48 formed at each end. A pair of inclined braces 52 stiffen the arm 47 with respect to the bearings 48.

A suitable centrally flanged pin 53 may be used to joint the link 49 to the arm 47. One of the supports for this arm assembly is shown in the lower right hand part of FIG. 1, wherein a bracket 54 is secured to the near side plate 31 and has a projecting support 56 suitably apertured at its outer end to receive the bearing 48.

Referring particularly to FIGS. 1, 2 and 4, there is illustrated a hold-down mechanism which pinches and thereby holds sheet metal moved along the top of a table 57, supby a round bar 62 joining hinge blocks 63, secured to the shoe 61 and hinge block 64 secured to transverse arm 66 spanning the distance from side plate 29 to side plate 31. The end of the hold-down is formed by a T member 67 directly over the cutter beam 16'and the cutter bar 17.

This pressure portion 67 or heel of the hold-down is normally urged upwardly by outboard compression springs (not shown). It is pushed downwardly against the cutter bar beam 16 and the cutter bar 17 by an arm 68 pivoted on a shaft 69 journaled in the end plates 29 and 31. This bar 69 is held against bending by vertical plates 71 welded above and below the bar 69. The rotation power for rotating the arm 68 is obtained from a pair of tension rods 72 connected to clevises 73 which form the hinge joint. The upper end of the tension rods are jointed to a cross arm 74 by clevises '76. This cross arm 74 rests upon a compressed spring 77 held in position by a through bolt 78 having its upper end held in a trunnion block 79. A spacer 80 keeps the cross arm 74 out of contact with a pair of lifter arms 81 having suitable notches 85 to receive trunnion pins 82 of the trunnion block 79. The left end (FIG. 1) of the lifter arms 81 are pivoted on a shaft 83 held in a block 84 secured to the top of a cross arm 86 spanning the distance between the side plate 29 and the side plate 31. Journaled in the other (righthand in FIG. 1) end of the lift arms 81 is a roller 87 which rides on the center cam or eccentric 39 on the crank shaft 26. This cam is 180 out of phase with the connecting rod earns 38 and hence when the cutter ram 23 is moving downwardly the lifter arms 81 are moving upwardly. This places a tension on the tension rods 72 causing them to pull upwardly and rotating the arm 68 on the shaft 69 pushing the T member 67 downwardly to hold sheet metal or other sheet material tightly while the movable cutter blade 22 is contacting it, cutting it and stretching the cut portions.

Illustrated in FIG. 1 on the lefthand side thereof is a post 88 supporting a pulley 89 about which passes a cable 91. This cable may be suitably connected to a weight (not shown) to cause an intermittent movement of the cable which in turn causes a material advancing device to operate, forcing sheet metal or other material forward on the table 57 when the hold-down heel d7 rises upwardly. Any conventional type of advancing device can be used and hence none isdescribed in this specification. "i

Referring particularly to FIGS. 6, 7 and 8, the mounting of the ram 23 is provided particularly in accordance with the invention. Spanning the space between the two side plates 29 and 32, is a bearing plate 92 securely bolted to both of these side plates (FIG. 1). This bearing plate 92 has two hardened machinedstrips 93 dovetailed into the bearing plate 92. The ram 23 has similar hardened and ground bearing strips 94 dovetailed into it and disposed opposite the bearing strips 93 and the bearing plate 92. Placed between these two pairs of hardened and ground bearing strips 03 and 94 are a plurality of hard alloy steel balls 96 held in a bronze ball retainer 97. This bronze retainer has a number of staggered holes 98 formed therein in which the balls freely roll. A continuous groove 99 is provided on each surface of the ball retainer 97 to retain grease for lubrication. By this means the ram 23 has a rolling ball contact with the bearing plate 92 and since the balls can be made to extreme accuracy in size, the sliding of the ram with respect to the bearing plate is without any tolerance whatsoever for practical purposes.

Referring again to FIGS. 6 and 7, the biasing means for resiliently holding the ram 23 in contact with the bearing plate 92 is illustrated. A rectangular framework is formed from a baseplate 101 and lateral supports 102 and a projected crossbar 103 is secured to the outer ends of these lateral members 102. A central plate 104 may be welded between the cross members 102 to add stiffness. Screw eyes 106 are threaded into the ram 23 and project through windows 107 in the bearing plate 92 and are engaged by a ring 108 on the end of a long rod 109. The rods 109 pass through apertures in the end bar 103 and compression springs 111 are placed over these ends and tied down by means of suitable nuts 112. The springs make it possible to place any selected tension on the rods 109 to pull the ram 23 against the bearing plate 92. It is a feature of the invention that the tension rods 109 are at an angle off of with respect to the reciprocating motion of the ram 23 and this is to counteract the weight of the ram 23 to reduce vibration in themachine. This angle is illustrated as angle A in FIG. 6 and the amount of angle depends upon the tension and ;upon the weight of the ram 23.

The mechanism of the ram bearing against the'bearing plate 2 permits the most minute adjustment of tolerances between the cutting blade 22 and the cutter bar 17. A standard tolerance in expanded material is of the thickness of the stock being expanded and this clearance or tolerance is illustrated in FIG. 6 by the letter C. It has been found possible to expand with high speed operation metal as thin as .005 inch which requires a clearance of of this amount, namely .0005. In standard expanding machines, this has not been heretofore possible because of the play of the reciprocating member in its guide. It is most important that the cutter blade 22 does not physically touch the cutter bar 17. as otherwise there would be wear and a machine embodying the present invention has operated for many months without the necessity of sharpening the blade 22 or the bar 17 It will also be remembered that the reciprocating ram 23 must also oscillate horizontally and this motion is easily accommodated by the balls 96. The dovetails of the bearing plate 92 are so constructed as to act as vertical stops for the ball retainer 97 but in actual practice this has not been found to be at all important. It has also been found that the engagement of the two rings 106 and 108 have a rolling engagement devoid of wear so that no replacement is needed for these parts.

The construction described permits the machine to be operated at a high rate of speed, for example, 300 r.p.m., which has been used with no difficulty whatsoever. The full floating ram 23 makes possible this rapid operation and the upper limits have not been explored.

Various modifications and accessories may be employed and one such is illustrated in FIG. 1. A shaft 115 supports a split block 116 which may be adjusted to any angle on the shaft and which in turn supports a' plate 117 shaped to have its outer end fit under the teeth of the cutter blade 22. This outer end of the plate 117 may be serrated in a complementary fashion to the cutter blade 22 (FIG. 3) and acts as a limit stop for the forward movement of sheet material being expanded. On automatic feed this entire device may be rotated out of engagement with any metal. a

While this invention has been described with respect to a specific embodiment thereof, it is not limited to this embodiment, but there is included within the claims all modifications and variations that come within the true spirit and scope of the invention.

I claim:

1. A metal expanding machine comprising:

(a) a stationary cutter bar;

(b) a movable cutter blade that reciprocates in a plane toward and away from the cutter bar and oscillates in said plane lengthwise of the bar;

(0) a bearing plate'having a fixed position with respect to the cutter bar and positioned in a plane parallel to said bar and parallel to said plane of movement of the blade;

(d) resilient means for holding the movable cutter blade away from said fixed cutter bar and against the fixed bearing plate to guide the blade during reciprocation and oscillation;

(e) and, means for reciprocating the cutter blade toward and away from the cutter bar and oscillating the blade on alternate reciprocations, whereby said cutter blade will shear sheet material disposed between it and the bar.

2. A metal expanding machine as set forth in claim 1 wherein the cutter blade has a serrated edge and the reciprocation thereof stops short of shearing off all of the sheet material disposed between the cutter bar and said serrated cutter blade to produce expanded sheet material.

3. A metal expanding machine as set forth in claim 1 wherein balls are disposed between the cutter blade and the bearing plate to obtain a ball bearing engagement between said blade and plate.

4. A metal expanding machine as set forth in claim 1 wherein the resilient means has a vector not at right angles to the plane of reciprocation, and in such a direction as to counteract the forces of gravity of said cutter blade.

5. A metal expanding machine wherein the cutting members are spaced from each other comprising: a stationary cutter bar; a bearing plate having a fixed position with respect to the cutter bar and generally parallel thereto; a movable cutter blade; means for reciprocating the cutter blade toward and away from cutter bar; means for oscillating the blade on alternate reciprocations; a universal joint having one end connected to the cutter blade on the side adjacent the bearing plate; and a member under tension connected to the other end of the universal joint, whereby said cutter blade is held in engagement with said bearing plate which acts as a guide for said reciprocating and oscillating cutter blade.

'6. A metal expanding machine as set forth in claim 5 wherein the bearing plate and the cutter blade have hard ened smooth surfaces disposed opposite each other and balls are disposed between these surfaces and roll between them to provide an anti-friction bearing member.

7. A metal expanding machine as set forth in claim 5 wherein a framework is mounted on the bearing plate on the side opposite the cutter blade; a rod is connected to the other end of the universal joint; and a spring is compressed by said rod against said frame work.

8. A metal expanding machine comprising: a stationary cutter bar; a bearing plate having a fixed position with respect to the cutter bar and generally parallel thereto; a movable cutter blade; resilient means for holding the movable cutter blade against the bearing plate for a sliding engagement with said bearing plate and a shearing action with said cutter bar; a hardened smooth strip mounted on the bearing plate opposite the cutter blade; a hardened smooth strip mounted on the cutter blade opposite said strip on the bearing plate; balls of uniform size disposed between the two hardened surfaces, whereby the actual contact between the cutter blade and the bearing plate is a rolling contact; means for reciprocating the cutter blade toward and away from the cutter bar; and means for oscillating the cutter blade along the cutter bar on alternate reciprocations.

9. In a metal expanding machine having a stationary cutter bar, and a cutter blade reciprocating and oscillating in a plane, structure for accurately guiding the blade into shearing relation with the bar comprising: a bearing plate generally parallel to the bar and parallel to the plane of reciprocating and oscillating movement of the cutter blade; balls disposed between the cutter blade and the bearing plate; and resilient means for forcing the blade against the balls so that the blade is accurately guided on the bearing plate without wear.

10. in a metal expanding machine having an elongated stationary cutter bar, and a moveable cutter blade that reciprocates toward and away from the bar and oscillates longitudinally of the bar, structure for accurately guiding the blade into a shearing relation with said cutter bar comprising: a fixed bearing plate generally parallel to the bar and parallel to the plane of oscillation and reciprocation of the blade; balls disposed between the blade and the bearing plate, and resilient means pressing the blade against the balls so that the blade is guided by said bearing plate while reciprocating and oscillating.

References (Iited by the Examiner UNITED STATES PATENTS 890,300 6/ 09 Reinhold 83--582 1,846,019 2/32 Bangser 30275 2,512,802 6/50 Koskinen 29--6.2 2,565,687 8/51 Hoier 12511 2,626,540 1/53 Eserkaln -13.1 2,707,995 5/55 Bibby 29-6.2 2,910,765 11/59 Heim 29148.4 2,922,458 1/60 Jensen 153--2 FOREIGN PATENTS 517,590 2/53 Belgium.

179,122 12/06 Germany.

25,999 10/97 Great Britain.

RICHARD H. EANES, 1a., Primary Examiner.

WHITMORE A. WILTZ, Examiner. 

1. A METAL EXPANDING MACHINE COMPRISING: (A) A STATIONARY CUTTER BAR; (B) A MOVABLE CUTTER BLADE THAT RECIPROCATES IN A PLANE TOWARD AND AWAY FROM THE CUTTER BAR AND OSCILLATES IN SAID PLANE LENGTHWISE OF THE BAR; (C) A BEARING PLATE HAVING A FIXED POSITION WITH RESPECT TO THE CUTTER BAR AND POSITIONED IN A PLANE PARALLEL TO SAID BAR AND PARALLEL TO SAID PLANE OF MOVEMENT OF THE BLADE; (D) RESILIENT MEANS FOR HOLDING THE MOVABLE CUTTER BLADE AWAY FROM SAID FIXED CUTTER BAR AND AGAINST THE FIXED BEARING PLATE TO GUIDE THE BLADE DURING RECIPROCATION AND OSCILLATION; (E) AND, MEANS FOR RECIPROCATING THE CUTTER BLADE TOWARD AND AWAY FROM THE CUTTER BAR AND OSCILLATING THE BLADE ON ALTERNATE RECIPROCATIONS, WHEREBY SAID CUTTER BLADE WILL SHEAR SHEET MATERIAL DISPOSED BETWEEN IT AND THE BAR. 